Early work on thermal control and energy storage using phase change materials (PCM) is able to be directly linked to the fast-paced developments in aeronautics and electronics in the middle of the twentieth century that was followed by the Space Program. A NASA document entitled “A Design Handbook for Phase Change Thermal Control and Energy Storage Devices” and authored by Humphries and Griggs, NASA Technical Paper 1074, (1977) provides a good overview of the state-of-the-art at that time and is widely referenced in a number of papers on thermal storage and PCM. Humphries and Griggs (1977) discuss a number of earlier works on utilization of metallic “fillers” to enhance the thermal conductivity of PCM. Understandably so, stationary inserts were widely adopted. These filler materials included metallic wool, foam and honeycomb that were introduced into a variety of fusible materials. The stationary inserts are limited in their uses due to size, lack of flexibility and other reasons.